System and method for determining selective catalytic reduction dosing system performance using an ammonia sensor
View Patent ↗A control system for a selective catalytic reduction (SCR) system includes a dosing control module, a comparison module, and a status determination module. The dosing control module controls a dosing system to inject a desired amount of ammonia into exhaust gas at a first location in an exhaust stream. The comparison module compares a measured amount of ammonia in the exhaust gas to the desired amount of ammonia, wherein the measured amount of ammonia is measured at a second location downstream from the first location and upstream from or within an SCR catalyst. The status determination module determines a pass/fail status of a component of the dosing system based on the comparison between the measured amount of ammonia and the desired amount of ammonia.
1. A control system for a selective catalytic reduction (SCR) system, comprising:
a dosing control module that controls a dosing system to inject a desired amount of ammonia into exhaust gas at a first location in an exhaust stream;
a comparison module that compares a measured amount of ammonia in the exhaust gas to the desired amount of ammonia, wherein the measured amount of ammonia is measured at a second location downstream from the first location and upstream from or within an SCR catalyst; and
a status determination module that determines a pass/fail status of a component of the dosing system based on the comparison between the measured amount of ammonia and the desired amount of ammonia,
wherein the dosing system includes a plurality of components, the plurality of components including a dosing agent injector, a dosing agent line, a dosing agent supply pump, a dosing agent supply, the SCR catalyst, and nitrogen oxide (NOx) sensors, and
wherein the status determination module is configured to generate a first fail status when the measured amount of ammonia is less than the desired amount of ammonia, and generate a second fail status when the measured amount of ammonia is greater than the desired amount of ammonia.
2. The control system of claim 1 , wherein the first fail status indicates that the dosing agent injector is clogged.
3. The control system of claim 1 , wherein the first fail status indicates that the dosing agent line is restricted or the dosing agent line has a leak.
4. The control system of claim 1 , wherein the first fail status indicates a low pressure dosing agent supply pump or that the dosing agent supply contains low quality dosing agent.
5. The control system of claim 1 , wherein the second fail status indicates a high pressure dosing agent supply pump or that the dosing agent injector is stuck in an open state.
6. The control system of claim 1 , wherein the second fail status indicates a low ammonia storage capacity of the SCR catalyst when the second location is within the SCR catalyst.
7. The control system of claim 1 , wherein based on at least one of dosing agent flow and dosing agent quantity measurements, the status determination module determines which of the plurality of components has failed.